Abstract A column liquid chromatographic (LC) method using UV detection for the determination of acemetacin and its metabolite indometacin in blood is described. The lower detection limit for both compounds is ca. 25 μg/l, the precision (coefficient of variation) is 6% for acemetacin and 10% for indometacin. The method is also suited for determination of both compounds in plasma, precisions in this case are even better than for blood, i.e. around 3% for both acemetacin and indometacin. Blood samples of three volunteers who had received 90 mg of acemetacin orally were analysed using the new method and very good agreement with results from a thin-layer chromatographic/fluorescence method was found.